Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

Jan Hidders schrieb:
> Well, that clarifies the discussion a bit. It's pretty obvious (though
> some in this group will probably argue otherwise) that the RM as a data
> model is rather clunky and low-level and that it is easy to come up with
> a data model that is more elegant and expressive. Many already have. But
> one should keep in mind that this is actually a feature, not a bug,
> because the point of RM is not just to be a good data model, its purpose
> is to be a good data model for the logical layer of the DBMS. That's
> similar, but not exactly the same.

> After looking a bit longer at your model I think FDM might be especially
> relevant, and probably even more so in it's modern incarnation that is
> the data model for Description Logics. It's very simple. Its
> formalization can be given in half a page or less. I can explain it to
> my students and probably to most participant in this group in 10
> minutes. It has an associated logic that is well know, very expressive
> and has nice computational properties. It doesn't have the limitation
> that the schema graph should be a lattice, but if you would so desire
> you could probably easily add a notion of "spanning lattice" that would
> allow the automatic guessing of paths between distant classes.